The thetan is both outside and inside the mest 1 body. It is not just inside. The only reason it is inside at all is that any field would penetrate the mest body. The mest body should not be thought of as a harbor or vessel for the theta being. A better example would be a sliver inserted unwantedly in the thumb where the thumb would be the theta being, the mest body the sliver.

The thetan flows electrical currents of command at the body. These hit pre-established ridges (areas of dense waves) and cause the body to perceive or act. The preclear takes from the body perception with tractor beams. He holds the body still or holds himself against it by wrapping a tractor (pulling) beam around it while placing a pressor (pushing) beam at his back to command himself into action.